Current work concentrates on the detailed evaluation of the validity of the cardiogreen clearance method for estimation of hepatic blood flow under grossly abnormal flow states. The cardiogreen estimations are compared with simultaneous electromagnetic flow measurements carried out in the dog on the portal vein and hepatic artery while producing experimental models which greatly increase and decrease the hepatic blood flow. A second study concerns the relationship of gastrointestinal blood flow to gastrointestinal function by simultaneous measurements of the organ blood flow and output of intestinal secretion from a variety of intestinal pouches. BIBLIOGRAPHIC REFERENCE: The fate of venous valves in the arterial tree. W. Weissenhofer, E. F. Schueller, and W. G. Schenk, Jr. Journal of Surgical Research, 17, 200, 1974.